Cogeneration system and method for controlling the same

ABSTRACT

A cogeneration system and a method for controlling the same have an advantage that it is easy to operate a cogeneration device because the operation of the cogeneration device can be controlled according to operation signals of an air conditioner, and have an effect that it is possible to make the best use of the generated electricity of the cogeneration device through an interconnection between the air conditioner and the cogeneration device.

The present disclosure relates to subject mater contained in priorityKorean Application No. 10-2005-0061798, filed on Jul. 8, 2005, which isherein expressly incorporated by reference in its entirety.

BACKGROUND CF THE INVENTION

1. Field of the Invention

The present invention relates to a cogeneration system, and moreparticularly to, a cogeneration system, which operates an engine and agenerator according to operation signals from an air conditioner, andwhich uses electricity produced by the generator and waste heatrecovered by the engine for the air conditioner, thereby improving theefficiency of the system, and a method for controlling the same.

2. Description of the Background Art

In general, a cogeneration system is a system that can produce bothelectricity and heat from a single energy source. The electricityproduced by the cogeneration system is supplied for use to electricalhousehold appliances, such as various kinds of household lightingequipment, heat pump type air conditioners, and so on, and the heatsource produced by the cogeneration system is used for hot water supply,warm water or the like.

FIG. 1 is a block diagram schematically showing a cogeneration system inaccordance with the prior art.

The cogeneration system in accordance with the prior art includes, asshown in FIG. 1, a generator 1 for producing electricity, an engine 4for driving the generator 1, an air conditioner 6 driven by theelectricity produced by the generator 2, waste heat recovery equipment 8for recovering waste heat generated by the engine 4, and a heatdemanding site 10, such as a heat storage tank, where waste heat isused.

The generator 2 and the air conditioner 6 are connected to a power linefor supplying electricity.

In the cogeneration system thus constructed, when the engine 4 isoperated, the generator 2 produces electricity by the driving force ofthe engine 4.

The electricity produced by the generator 2 is supplied to the airconditioner 6 via the power line 12, to thus operate the air conditioner6.

The waste heat generated by the engine 4 is recovered by the waste heatrecovery equipment 8, and used in the heat demanding site 10.

When the engine 4 is stopped, the generator 2 is also stopped, to thusstop the power supply to the air conditioner 6 from the generator 2.

However, the cogeneration system in accordance with the prior art has aproblem in that only the electricity produced by the generator 2 issupplied to the air conditioner 6, and the waste heat recovered by theengine 4 is only utilized for hot water supply, warm water, or the likein the heat demanding site, so that it is impossible to maximize theefficiency of the system.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to solve the aboveprior art problem, and provide a cogeneration system, which can improvethe efficiency of the system by supplying waste heat recovered from adriving source to a compressor suction side of an air conditioner, andwhich can remotely control the operations of an engine and a generatoraccording to an operating state of the air conditioner, and a method forcontrolling the same.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein,there is provided a cogeneration system, including: a cogenerationdevice for supplying at least one of electricity and heat to an airconditioner; and a cogeneration device controller for controlling theoperation of the cogeneration device according to operation signals fromthe air conditioner.

The cogeneration device controller is supplied with electricity from anexternal power source,

The cogeneration system further includes an air conditioner controllersupplied with electricity from an en external power source, forcontrolling the air conditioner.

The air conditioner includes an indoor unit supplied with electricityfrom an external power source and an outdoor unit supplied withelectricity from the generator, and the cogeneration device controllercontrols the operation of the cogeneration device according to operationsignals from the indoor unit.

The air conditioner includes an indoor unit supplied with electricityfrom an external power source, an outdoor unit supplied with electricityfrom the generator, and a remote control for wirelessly operating theindoor unit, and the cogeneration device controller controls theoperation of the cogeneration device according to operation signals fromthe indoor unit.

The cogeneration device includes a generator for generating electricityand a driving source for driving the generator and generating heat.

The cogeneration device controller controls the driving of the drivingsource according to the operation signals from the air conditioner.

The cogeneration device controller controls the power supply to the airconditioner from the generator according to the operation signals fromthe air conditioner.

The cogeneration system further includes a waste heat recovery unit forsupplying waste heat recovered from the driving source to the airconditioner.

The air conditioner and the cogeneration device controller perform datacommunication by the RS-485 communication protocol.

The cogeneration system further includes a monitoring device connectedto the cogeneration device controller, for monitoring the operations ofthe cogeneration device and the air conditioner.

In accordance with another aspect of the present invention, there isprovided a method for controlling a cogeneration system, including:applying power to an indoor unit of an air conditioner and a controllerof a cogeneration device from outside; transmitting operation signalsfrom the indoor unit of the air conditioner to the controller of thecogeneration device; if the signal transmitted in the transmitting ofoperation signals is an ON signal, operating the cogeneration device bythe controller of the cogeneration device; and operating thecogeneration device to supply produced electricity to an outdoor unit ofthe air conditioner.

If the operation signals outputted in the transmitting of an operationsignal are OFF signals, the cogeneration device controller stops thecogeneration device.

If the operation signals outputted in the transmitting of operationsignals are OFF signals, and the OFF signals are maintained for apredetermined time, the operation of the cogeneration device is stopped.

If the operation signals outputted in the transmitting of operation issignals are OFF signals, the power supply from the cogeneration deviceto the outdoor unit is cut off, and thereafter, the driving source ofthe cogeneration device is stopped.

The cogeneration system and the method for controlling the same inaccordance with the invention have an advantage that it is easy tooperate the cogeneration device because the operation of thecogeneration device can be controlled according to operation signals ofthe air conditioner, and have an effect that it is possible to make thebest use of the generated electricity of the cogeneration device throughan interconnection between the air conditioner and the cogenerationdevice.

Additionally, the air conditioner controller and the cogeneration devicecontroller are supplied with electricity from an external power source,and the compressor, fan, etc. of the air conditioner are supplied withelectricity from the generator, so that it is possible to properly usethe generated electricity of the cogeneration system and the externalpower source, thereby maximizing the utilization of the generatedelectricity of the cogeneration device and minimizing the utilizationfactor of the external power source by

Additionally, the suction side of the compressor is pre-heated usingwaste heat recovered b the engine of the cogeneration device, so thatthe efficiency of the compressor is improved, to thus reduce unnecessarywaiting time when driving the cogeneration device.

Additionally, if the operation signals outputted to the cogenerationdevice controller from a plurality of remote controls are all OFFsignals, and the OFF signals are maintained for a predetermined time,the operation of the cogeneration device is stopped, thereby preventinga malfunction thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a block diagram schematically showing a cogeneration system inaccordance with the prior art;

FIG. 2 is a block diagram schematically showing a cogeneration system inaccordance with the present invention; and

FIG. 3 is a sequential chart showing a method for controlling acogeneration system in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an exemplary embodiment of a cogeneration system and amethod for controlling the same in accordance with the invention will bedescribed with reference to the accompanying drawings.

There may be a plurality of exemplary embodiments of the cogenerationsystem and the method for controlling the same in accordance with theinvention, but the most preferred embodiment will be describedhereinafter.

FIG. 2 is a block diagram schematically showing a cogeneration system inaccordance with the present invention.

The cogeneration system in accordance with the invention, includes, asshown in FIG. 2, an air conditioner 50, a cogeneration device 60 forsupplying electricity and heat to the air conditioner 50, and acontroller 70 for controlling the operation of the cogeneration device60 according to operation signals from the air conditioner 50.

A description of the air conditioner 50 will be made with respect to aheat pump type air conditioner.

The air conditioner 50 includes a plurality of indoor units 51 installedindoors and supplied with electricity from an external power source 80,a plurality of outdoor units 52 installed outdoors and supplied withelectricity from the cogeneration device 60, and a plurality of remotecontrols for wirelessly operating the plurality of indoor units 51,respectively.

Here, the external power source 80 is a commercial power source that issupplied from an electric power company.

The air conditioner further includes a controller (not shown) suppliedwith electricity from the external power source 80, for controlling theoperations of the indoor units 51 and the outdoor units 52. The airconditioner controller (not shown) is installed in each of the indoorunits 51 and outdoor units 52.

Therefore, the plurality of indoor units 51 and outdoor units 52 areconnected in parallel to the external power source 80 by a first powerline 81.

The plurality of indoor units 51 and outdoor units 52 are connected inparallel by a first communication line 91 so as to perform datacommunication by the RS-485 communication protocol.

The cogeneration device 60 includes a generator 61 for generatingelectricity, a driving source for driving the generator 61 andgenerating heat, and a waste heat recovery unit (not shown) forrecovering waste heat generated from the driving source and supplyingthe waste heat to the suction side of a compressor (not shown) in theoutdoor units 52.

An engine 62, a fuel cell, or the like is used as the driving force, andthus a description thereof will be made with respect to the engine 62.

The cogeneration device 60 is connected to the outdoor units 52 by asecond power line 82 so as to supply the electricity produced by thegenerator 61 to the outdoor units 52.

The cogeneration device controller 70 is connected to the external powersource 80 by the first power line 81 so as to be supplied withelectricity from the external power source 80.

The cogeneration device controller 70 controls the operation of thecogeneration device 60 according to operation signals from the airconditioner 50, and thus will be described with respect to a case inwhich the cogeneration device 70 is constructed so as to control theoperation of the cogeneration device 60 by operation signals inputtedfrom the remote controls 53.

The cogeneration device controller 70 and the outdoor units 52 areconnected by a second communication line 92 so as to perform datacommunication by the RS-485 communication protocol, while thecogeneration device controller 70, the generator 61, and the engine 62are connected by a third communication line 93 so as to perform datacommunication by the RS-232 communication protocol.

Additionally, the cogeneration system further includes a monitoringdevice connected to the cogeneration device controller 70 by a fourthcommunication line 94, for monitoring the operations of the cogenerationdevice 60 and the air conditioner 50.

The method for controlling the thus-constructed cogeneration system inaccordance with the invention will now be described.

FIG. 3 is a sequential chart showing a method for controlling acogeneration system in accordance with the present invention.

In the method for controlling the cogeneration system in accordance withthe invention, as shown in FIG. 3, in a first step, power is appliedfrom the external power source to the air conditioner controller and acogeneration device controller.

In a second step, if a user operates the remote controls, the remotecontrols output operation signals of the indoor units.

Here, if the user operates the remote controls in order to turn on theindoor units, the remote controls output ON signals to the airconditioner controller.

The ON signal outputted from the remote controls is also received by thecogeneration device controller by RS-485 communication.

In a third step, the cogeneration device controller operates thecogeneration device according to the ON signals outputted from theremote controls.

That is, the cogeneration device controller operates the engine, and thegenerator is driven by the engine.

In a fourth step, the electricity produced by the generator is suppliedto the outdoor units.

That is, the electricity produced by the generator is supplied to loadswith relatively high power consumption, such as a compressor, a fan, apump, etc. in the indoor units.

Accordingly, it is possible to make the best use of the electricity fromthe generator, and minimize the use of the external power source.

Furthermore, the compressor of the indoor units is pre-heated usingwaste heat of the cooling water that has cooled down the engine andwaste heat of the exhaust gas exhausted from the engine, so that theefficiency of the compressor and the utilization efficiency of wasteheat can be increased.

Meanwhile, in the second step, if the operation signals outputted fromthe plurality of remote controls to the cogeneration device are all OFFsignals, and the OFF signals are maintained for a predetermined time,this is recognized as an operation stopped state of the indoor units.

Therefore, the cogeneration device controller stops the engine aftercutting off the supply of the electricity produced by the generator tothe outdoor units.

Although the cogeneration system and the method for controlling the samein accordance with the invention have been described with reference tothe illustrated drawings, the present invention is not limited to theembodiments and drawings disclosed in this specification, and can beapplied within the scope of the technical concept of the presentinvention.

The cogeneration system and the method for controlling the same inaccordance with the invention have an advantage that it is easy tooperate the cogeneration device because the operation of thecogeneration device can be controlled according to operation signals ofthe air conditioner, and have an effect that it is possible to make thebest use of the generated electricity of the cogeneration device throughan interconnection between the air conditioner and the cogenerationdevice.

Additionally, the air conditioner controller and the cogeneration devicecontroller are supplied with electricity from an external power source,and the compressor, fan, etc. of the air conditioner are supplied withelectricity from the generator, so that it is possible to properly usethe generated electricity of the cogeneration system and the externalpower source, thereby maximizing the utilization of the generatedelectricity of the cogeneration device and minimizing the utilizationfactor of the external power source by

Additionally, the suction side of the compressor is pre-heated usingwaste heat recovered b the engine of the cogeneration device, so thatthe efficiency of the compressor is improved, to thus reduce unnecessarywaiting time when driving the cogeneration device.

Additionally, if the operation signals outputted to the cogenerationdevice controller from a plurality of remote controls are all OFFsignals, and the OFF signals are maintained for a predetermined time,the operation of the cogeneration device is stopped, thereby preventinga malfunction thereof.

1. A cogeneration system, comprising: a cogeneration device forsupplying at least one of electricity and heat to an air conditioner;and a cogeneration device controller for controlling the operation ofthe cogeneration device according to operation signals from the airconditioner.
 2. The cogeneration system of claim 1, wherein thecogeneration device controller is supplied with electricity from anexternal power source.
 3. The cogeneration system of claim 1, furthercomprising an air conditioner controller supplied with electricity froman en external power source, for controlling the air conditioner.
 4. Thecogeneration system of claim 1, wherein the air conditioner comprises anindoor unit supplied with electricity from an external power source andan outdoor unit supplied with electricity from the generator.
 5. Thecogeneration system of claim 4, wherein the cogeneration devicecontroller controls the operation of the cogeneration device accordingto operation signals from the indoor unit.
 6. The cogeneration system ofclaim 4, wherein the air conditioner further comprises a remote controlfor wirelessly operating the indoor unit, and the cogeneration devicecontroller controls the operation of the cogeneration device accordingto operation signals from the indoor unit.
 7. The cogeneration system ofclaim 1, wherein the cogeneration device comprises a generator forgenerating electricity and a driving source for driving the generatorand generating heat.
 8. The cogeneration system of claim 7, wherein thecogeneration device controller controls the driving of the drivingsource according to the operation signals from the air conditioner. 9.The cogeneration system of claim 7, wherein the cogeneration devicecontroller controls the power supply to the air conditioner from thegenerator according to the operation signals from the air conditioner.10. The cogeneration system of claim 7, further comprising a waste heatrecovery unit for supplying waste heat recovered from the driving sourceto the air conditioner.
 11. The cogeneration system of claim 1, whereinthe air conditioner and the cogeneration device controller perform datacommunication by the RS-485 communication protocol.
 12. The cogenerationsystem of claim 1, further comprising a monitoring device connected tothe cogeneration device controller, for monitoring the operations of thecogeneration device and the air conditioner.
 13. A cogeneration system,comprising: an air conditioner; an air conditioner controller suppliedwith electricity from an external power source, for controlling the airconditioner; a generator for supplying electricity to the airconditioner; a driving source for driving the generator and generatingheat; and a controller supplied with electricity from an external powersource, for controlling the operation of the generator according tooperation signals from the air conditioner.
 14. The cogenerations systemof claim 13, wherein the air conditioner comprises an indoor unitsupplied with electricity from an external power source and an outdoorunit supplied with electricity from the generator.
 15. The cogenerationsystem of claim 14, wherein the air conditioner further comprises aremote control for wirelessly operating the indoor unit, and thecogeneration device controller controls the operation of thecogeneration device according to operation signals from the indoor unit.16. A method for controlling a cogeneration system, comprising: applyingpower to an indoor unit of an air conditioner and a controller of acogeneration device from outside; transmitting operation signals fromthe indoor unit of the air conditioner to the controller of thecogeneration device; if the signal transmitted in the transmitting ofoperation signals is an ON signal, operating the cogeneration device bythe controller of the cogeneration device; and operating thecogeneration device to supply produced electricity to an outdoor unit ofthe air conditioner.
 17. The method of claim 16, wherein if theoperation signals outputted in the transmitting of operation signals areOFF signals, the cogeneration device controller stops the cogenerationdevice.
 18. The method of claim 16, wherein if the operation signalsoutputted in the transmitting of operation signals are OFF signals, andthe OFF signals are maintained for a predetermined time, the operationof the cogeneration device is stopped.
 19. The method of claim 16,wherein if the operation signals outputted in the transmitting ofoperation signals are OFF signals, the power supply from thecogeneration device to the outdoor unit is cut off.
 20. The method ofclaim 19, wherein once the power supply of the cogeneration device iscut off, the driving source of the cogeneration device is stopped.